1. Field of the Invention
The present invention relates to an organic-metal-compound-containing solution used in manufacturing an electron-emitting device, and to methods of manufacturing an electron-emitting device, an electron source, and an image forming apparatus using the organic-metal-compound-containing solution and, more particularly, to the manufacturing method using an ink-jet method and the solution used in the manufacturing method.
2. Related Background Art
As conventional electron-emitting devices, two types of electron-emitting devices, i.e., a thermionic emission device and a cold-cathode emission device, are known. As the cold-cathode emission device, a field emission type device (to be referred to as "FE type" hereinafter), a metal/insulating layer/metal type (to be referred to as "MIM type" hereinafter) emission device, and a surface conduction type electron-emitting device are known. For example, as a FE type device, an device disclosed in W. P. Dyke & W. W. Dolan, "Field Emission", Advances in Electronics and Physics, 8, 89 (1956), C. A. Spindt, "PHYSICAL Properties of Thin-Film Field Emission Cathodes with Molybdenum Cones", J. Appl. Phys., 47, 5248 (1976), or the like is known.
As an MIM type emission device, device disclosed in C. A. Mead, "Operation of Tunnel-Emission Devices", J. Appl. Phys., 32, 646 (1961) or the like is known.
As a surface conduction type electron-emitting device, a device disclosed in M. I. Elinson, "The Emission of Hot Electrons and the Field Emission of Electrons from Tin Oxide," Radio Eng. and Electron Pys., 10, 1290 (1965) or the like is known.
A surface conduction type electron-emitting device uses a phenomenon in which electron emission occurs by causing a current to flow into a small thin film formed on a substrate in a direction parallel to the film plane. As the surface conduction type electron-emitting device, the above electron-emitting device using an SnO.sub.2 thin film and obtained by Elinson, an electron-emitting device using an Au thin film [G. Dittmer, "Electrical Conduction and Electron Emission of Discontinuous Thin Films," Thin Solid Films, 9, 317 (1972)], an electron-emitting device using an In.sub.2 O.sub.3 /SnO.sub.2 thin film [M. Hartwell and C. G. Fonstad, "Strong Electron Emission from Patterned Tin-Indium Oxide Thin Films," IEEE Trans. ED Conf., 519 (1975)], an electron-emitting device using a carbon thin film [Hisashi Araki et al., "Electroforming and Electron Emission of Carbon Thin Films," Journal of the Vacuum Society of Japan, Vol. 26, 1, 22 (1983), or the like has been reported.
As a schematic device arrangement of the above surface conduction type electron-emitting devices, the device arrangement obtained by M. Hartwell will be described below with reference to FIG. 7. Referring to FIG. 7, reference numeral 1 denotes a substrate. Reference numeral 4 denotes an electroconductive thin film consisting of a metal oxide thin film or the like formed by sputtering in an H-shaped pattern. The electroconductive thin film 4 is subjected to a current conduction treatment called energization forming to form an electron emission portion 5. The length L and width W' of the device in FIG. 7 are set to about 0.5 mm to 1 mm and about 0.1 mm, respectively.
In the above conventional surface conduction type electron-emitting device, before electron emission is performed, the electroconductive thin film 4 is generally subjected to a current conduction treatment called energization forming to form the electron emission portion 5. More specifically, in the energization forming, a DC voltage or a voltage which very slowly increases, e.g., about 1 V/min., is applied across both the ends of the electroconductive thin film 4 to energize the electroconductive thin film 4, and the electroconductive thin film 4 is locally broken, deformed, or deteriorated to form the electron emission portion 5 which is in an electrically high resistance state. In the electron emission portion 5, fissures are formed in a part of the electroconductive thin film 4, and electron emission occurs from a portion near the fissures. In the surface conduction type electron-emitting device which has been subjected to the energization forming treatment, a voltage is applied to the electroconductive thin film 4 to cause a current to flow into the device, thereby causing the electron emission portion 5 to emit electrons.
As a method of forming the electroconductive thin film, a method of directly forming an electroconductive material on a substrate by thin film deposition such as vacuum evaporation or sputtering is known. As another method, a method of coating a solution of an organic metal compound or the like on a substrate and heating to decompose it into a metal or a metal oxide is known. According to these methods, since a vacuum apparatus for film formation is not required, advantages in production, such as a reduction in manufacturing cost, can be obtained.
As described above, to apply an organic metal compound solution on a substrate to form an electroconductive film, the following patterning method is used. That is, after a mask having an opening having a predetermined pattern is formed on the substrate, the organic metal compound solution is coated on the substrate by dipping, spin-coating, spray-coating, or the like, and the coated film is heated and decomposed to obtain a metal or a metal oxide. Thereafter, the mask is removed to obtain an electroconductive film having a predetermined shape. However, if the solution coated on the entire surface of the substrate need not be patterned, then when an electron source in which a large number of devices are arranged on a large substrate is to be manufactured, advantages in manufacturing can be obtained.